The present invention pertains generally to drainage systems for emptying vehicle holding tanks at a stationary dump station.
Holding tanks are commonly provided on vehicles including motor homes and trailers and require periodic emptying into a stationary sanitary system termed a dump station. Well known in the present field of invention are lengths of flexible tubing with a corrugated wall which are provided with couplings at their opposite ends for connection to the vehicle drain and to a sanitary system. The use of such conduits incurs a cleaning problem in that such conduits do not lend themselves to thorough cleaning and frequently matter left therein will result in an unpleasant odor in the vehicle upon stowage of the conduit. Further, the cleaning task is objectionable in that it is normally accomplished using a garden hose for flusing into a suitable receptacle. At the end of a flushing operation, the flexible tubing must be drained and stowed aboard the vehicle, frequently a messy task.
Attempts have been made to utilize rigid conduits in such drainage systems but for one reason or another the same are not apparently in wide use. A drawback to rigid conduits is the lack of adequately sealing same resulting in discharge of fluid waste between the vehicle drain and the sanitary system inlet.
Further contributing to the task of draining a vehicle holding tank is the task of positioning of a vehicle so as to properly locate its drain relative the sanitary system and which may entail repeated efforts. As vehicles equipped with holding tanks are sizeable, the precise positioning of the vehicle with respect to a sanitary system inlet can require considerable effort.
In the prior art U.S. Pat. No. 3,496,959 discloses telescopic tubes of rigid construction served at their inlet and outlet ends by flexible hoses. Use entails the installation of the hoses with clamps at several points and the support of the telescopic tubes by temporary engagement with a bracket 26 supporting the tubes in an inclined manner. The tubes are supported by a bracket externally of the vehicle during travel which is impractical for current recreational vehicles in view of restricted ground clearance.
U.S. Pat. No. 3,730,228 shows telescopic tubing supporting a flexible hose therein to prevent sagging of the latter and does not contribute toward the solution of other problems encountered when such are used.
U.S. Pat. No. 4,650,224 discloses telescopic tubes in a drain system wherein corrugated tubing is utilized to couple the tubing to a vehicle drain outlet. O-rings are utilized for sealing the ends of telescoped tubular members which are provided with bayonet type couplings.
U.S. Pat. No. 4,223,702 utilizes telescopic tubes to impart rigidity to a flexible drainage hose extending therethrough.
U.S. Pat. No. 5,323,813 discloses telescopic tubing and utilizes flexible or corrugated wall tubing at both inlet and outlet ends which hinders proper flushing of the tubing after use.